AMC 401 engine for my 1972 Duster

MUCH heavier engine and IMO not worth doing. Get yourself a 5.9L or even 5.2L Magnum and stick that in there. The Chrysler 727 won't bolt up, and the AMC Torque Command 727 won't bolt to the chassis. So IMO the 401 is cool, but belongs in a Gremlin or Pacer.